I understand 2" drain pipe is minimum code for most places now however I have 1 1/2" brass coming through a concrete slab in a strata building. BC here requires 'non-combustible' parts for the entire path even to the fixture thus almost all available products are ineligible. I've seen however a good number of clamping floor drains made of cast iron but not any of brass. Can anyone help with the following questions I have to sort as I attempt to install a built up shower base on the concrete slab. There is poured concrete around the 1 1/2" pipe so I can chisel a bit away to sink a drain assembly a bit but I'm talking less than 1/2" below the plane of the slab to avoid collateral damage for the unit below.

Does anyone know of a non-combustible floor drain which can be fitted to 1 1/2" brass drain. I intend to use a membrane and need the grate to be aesthetically acceptable for higher end residential.

Would a cast iron assembly work - ie, an adapter union to the brass? Is dielectric union then necessary? Any specific floor drains you'd recommend?

Most ideal would be a non-combustible flange assembly able to accept a linear drain insert but I've not found anything close to that.

There are 1½" NPT cast iron clamping drains available. Oatey has one, #42192. In your installation, the lower half will stick up a ways above the floor, so a thick preslope will be needed. The brass pipe is threaded, correct?

Thanks Steve - however that's what I'm trying to avoid in the height of that drain. The distance from the clamp to surface of the drain isn't something I could see working. Ideally it would be something like a low profile drain flange that would accept an insert or screw type adjustable drain. I've had another look at this and I'm now thinking it's a 1 1/2" copper pipe (no thread) arising through the slab. After removing the tub and brass overflow I'm left with 1" of pipe above the slab to work with. I can take some of the concrete fill out but don't want to take the whole thing out.